Hydraulic Whipstock Anchor

ABSTRACT

A whipstock anchor is hydraulically set and locked in the set position. Release occurs with a pull induced component failure that relieves hydraulic pressure that allows the slips to retract. Release can occur with a remotely actuated circuit that burns a retainer for a piston whose movement opens a vent or initiates a chemical reaction to undermine a lock ring. Movement of a single cone or opposed cones extends the slips. The cone angles being different (cone angles do not have to be different, it is preferred to have the slip angles different) adds a skew to the slips and positions the top of the whipstock against the tubular top in a horizontal run. A bottom cap is removable to convert to setting by set down weight or to attach a hydraulically operated packer below the slips. Slips can be extended with radial movement of pistons.

FIELD OF THE INVENTION

The field of the invention is hydraulic anchor assemblies for whipstocksin borehole use and more particularly anchors that release in a varietyof ways, or cock the whipstock or that can be modularly built tooptionally add setting capability with setting down weight or bereconfigured to add a hydraulically actuated sealing functionality tothe anchor.

BACKGROUND OF THE INVENTION

Whipstocks are long tapered ramps that are secured in a tubular stringto guide a mill assembly laterally to make an exit through the tubularwall for the start of a lateral bore. The taper angle is gradual, in theorder of about 1-3 degrees. The ramp is typically oriented with a bottomhole assembly so that the ramp faces the direction of the desiredlateral. In some instances there can be a need to have the lateral exitin a downward direction off a horizontal bore. In such cases it isadvantageous to ensure that the top of the whipstock is pushed againstthe top of the horizontal run so that after the window in the casing hasbeen milled a drilling assembly that will be deployed on a subsequentrun will pass freely through the window in the casing without engagingthe top of the whipstock.

Anchors that hydraulically extend from one side of a whipstock lower endto skew the whipstock are described in U.S. Pat. No. 6,843,314. A designthat uses a nonparallel slip face to the surrounding tubular for skewingthe whipstock is described in U.S. Pat. No. 8,505,651. Another way awhipstock is mounted off center in a surrounding tubular is to use aneccentrically mounted sealing element that is set with set down weightafter an anchor is set mechanically or hydraulically is shown in US2015/0345241. A non-releasing anchor that sets hydraulically and has theset position locked with a body lock ring is shown in U.S. Pat. No.5,154,231. A mechanically actuated whipstock anchor using relativemovement of opposed inclined surfaces is shown in U.S. Pat. No.6,360,821.

What is needed and provided by the illustrated embodiments of thepresent invention is a hydraulic whipstock anchor that holds the set andcan be released in a variety of ways. One way is to vent trappedhydraulic pressure that holds the slips out and one way that is done isto pull tension and fail a component that lets the hydraulic pressurerelieve so that the slips can retract. Another way to slip release is toremotely close a circuit that allows electrical current to heat andbreak a wire to release a piston whose movement opens a vent port.Alternatively release of the piston can allow fluids to pass through aport that undermine a mechanical lock ring that holds the slipsextended. The slips can be wedged out radially with axial movement of acone or by radial piston movement with the slips on the piston ends. Theanchor design can be modular so that removal of an end cap allowsalternative slip setting by setting down weight or the ability to add apacker component to the housing end that is actuated hydraulically withthe slips. Cocking of the whipstock top end to an upper part of ahorizontal run for a downward casing exit can be accomplished with rampssloped at different angles that induce a turning moment on the slips torotate the whipstock body. Preferably the slips will be offset along theaxis of the whipstock to further increase the turning moment to rotatethe whipstock body. Alternatively, the slip assembly can be mounted onan axis that skews with respect to the whipstock body to impart aturning moment to the whipstock body for desired positioning of the topend of the whipstock. These and other aspects of the present inventionwill be more readily apparent to those skilled in the art from a reviewof the description of the preferred embodiments and the associateddrawings while recognizing that the full scope of the invention is to bedetermined from the appended claims.

SUMMARY OF THE INVENTION

A whipstock anchor is hydraulically set and locked in the set position.Release occurs with a pull induced component failure that relieveshydraulic pressure that allows the slips to retract. Release can occurwith a remotely actuated circuit that burns a retainer for a pistonwhose movement opens a vent or initiates a chemical reaction toundermine a lock ring. Movement of a single cone or opposed conesextends the slips. The cone angles being different adds a skew to theslips and positions the top of the whipstock against the tubular top ina horizontal run. A bottom cap is removable to convert to setting by setdown weight or to attach a hydraulically operated packer below theslips. Slips can be extended with radial movement of pistons.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a section view of a locking anchor design with a tensilerelease;

FIG. 1a is the view along line 1 a-1 a of FIG. 1

FIG. 1b is an enlarged view of the slips in FIG. 1 showing the taperangle difference;

FIG. 2 is a section view of an alternative embodiment showing a skew inthe anchor body with respect to the whipstock axis;

FIG. 2a is the view along line 2 a-2 a of FIG. 2

FIG. 3 is a section view of an embodiment showing opposed cone movementfor slip extension;

FIG. 3a is the view along line 3 a-3 a of FIG. 3;

FIG. 3b is an outside view of the slip retainer of FIG. 3;

FIG. 3c is a detailed section view of the slips in FIG. 3 showingdiffering opposed taper angles;

FIG. 4 is a section view of an embodiment that releases with a remotesignal that allows a piston to move to release hydraulic pressure;

FIG. 4a is the view along line 4 a-4 a of FIG. 4;

FIG. 5 is a section view of an embodiment that moves a slip radiallywith a radially oriented piston and releases with a remote signal thatvents hydraulic pressure;

FIG. 5a is an outside view of the slips showing a retainer for themoving slips;

FIG. 6 illustrates a modular hydraulically operated packer that can bemounted to the slip assembly;

FIG. 7 is a section view of an anchor that is releases with a remotesignal that allows a piston to move to release an agent to undermine abody lock ring for anchor release;

FIG. 7a is a view along line 7 a-7 a of FIG. 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, a whipstock 10 has a ramp 12 and an associatedhydraulic line 14 that typically is run behind the ramp 12 to protectthe line 14 from the advancing window mill that is not shown. A checkvalve 16 in line 14 allows flow one way into passage 18 to chamber 20defined by cap 22 secured at thread 24 to housing 26. Cone 32 is sealedwith seals 28 and 30 so that built up pressure in chamber 20 moves cone32 in the direction of arrow 34 toward the housing 26. Two slips 36 areshown at 180 degree spacing although different spacing and number ofslips is contemplated. The slips 36 have external carbide or hardenedinserts 38 to dig into the surrounding tubular that is not shown tosupport the whipstock 10. A biasing spring 40 pushes between arespective slip 36 and a retainer 42 that limits the outward travel ofeach slip 36. A lock ring 44 is moved along ratchet profile 46 as cone32 moves in the direction of arrow 34 to prevent reverse movement of thecone 32. The lock ring 44 in effect maintains the set of the slips 36against the surrounding tubular that is not shown. Preferably rampsurfaces 48, 50, 140 and 142 have the same slope. Slip surface 144 has aslightly smaller slope than ramp surfaces 48, 50, 140 and 142, and slipsurface 146 has a slightly greater slope than ramp surfaces 48, 50, 140and 142 to put whipstock axis 152 into a cocked position with respect tohorizontal axis 52 as schematically illustrates in FIG. 1b . In apreferred embodiment the angle difference on opposed slip surfaces 144and 146 is a degree but larger or even smaller differences arecontemplated to skew the slip orientation in opposed directions asbetween slips with 180 degree spacing. The desired result is a skew isimparted to the whipstock 10 to keep its upper end (not shown) againstthe inside diameter (ID) of a horizontal pipe for making a downwardlyoriented window exit. In essence the slips hardened inserts 38 areparallel to each other but both are skewed with the whipstock axis 152to impart a rotational moment to whipstock 10 as indicated by arrows 54and 56. Preferably ramps surfaces 48 and 50 will be closer to the top ofthe whipstock than ramps surfaces 140 and 142 to provide a fulcrumeffect to create a greater force to keep the top of the whipstock pushedtighter against the ID of the horizontal pipe. Preferably the slopingsurfaces 144 and 146 on the slips 36 are parallel to their respectiveopposing ramp surfaces 48, 140, 50, and 142 on cone 32 and housing 26however, some angular difference is also contemplated as an option.Hardened inserts 38 are imbedded into slips 36 on either side ofretainer 42. Width 148 on one side of slip 36 is greater than width 150on the other side of slip 36. Having different widths on either side ofslip 36 makes it possible to use identical slips at 180 degree spacingin housing 26 and have them installed in the proper orientation.Retainers 42 cannot be installed if slips 36 are installed in housing 26incorrectly. Whipstock axis 152 will also be rotated if the slope ofslip surfaces 144 and 146 are identical and housing ramp angle 48 islarger than ramp angle 140 and cone ramp angle 50 is smaller than rampangle 142. Mandrel 58 has a necked down portion 60 so that when atensile force is exerted on the whipstock 10 with slips 36 extended tothe surrounding tubular the cone 32 and lock ring 44 retain the lowerend of the mandrel 58 because the slips 36 bite into the surroundingtubular. The tensile force on mandrel 58 increases until a tensilefailure occurs at necked down portion 60. As the mandrel 58 breaks at 60the pressure in chamber 20 dissipates and the housing 26 has the abilityto move up and away from the set slips 36 so they are no longer wedgedagainst the surrounding tubular. The cone 32 is retained by cap 22 afterthe tensile failure at 60. It should be noted if the hydraulic system isfilled with incompressible fluid the check valve 16 can hold thepressure against the set slips 36 using cone 32, however, the body lockring 44 insures that the slips 36 cannot back away from the surroundingtubular after the set.

FIG. 2 is somewhat different than FIG. 1 in that a single radiallymoving slip 36 is used and is opposed by segment 62 with hardened orcarbide inserts 64. Cone 32 is modified to have a taper only under thesingle slip 36 whose extension brings the inserts 64 to the surroundingtubular wall. In this version the hardened inserts 38 in slip 36 areparallel to hardened inserts 64 in segment 62, but are at a small anglewith respect to whipstock axis 152 of the whipstock 10 such thatextension of slip 36 until inserts 64 reach the surrounding tubular 180degrees away will wind up pushing the top end of the whipstock againstthe surrounding pipe to keep it out of the way of the advancing windowmill. Housing 26 is conically shaped below arrows 66 to provideclearance when the bottom of the whipstock 10 is rotated toward thetubing wall. The skew in FIG. 2 can be further enhanced with theorienting of the one slip 36 akin to the manner previously described inthe discussion of FIG. 1 b.

FIG. 3 is the same as FIG. 1 with the exception that there are opposedpistons that move on opposite sides of the slips 36. Mandrel 58 that wasthreaded to housing 26 in FIG. 1 is now slidably mounted after breakingshear pin 68. A lock ring 70 only allows mandrel 58 to move in thedirection of arrow 72 with its final position locked in with lock ring70. As before cone 32 moves in an opposite direction toward slips 36 andits set position is locked with lock ring 44. Pin 74 extends fromhousing 26 into slot 76 in mandrel 58 to prevent relative rotationbetween the two. As before release occurs with a tensile failure atdecked down portion 60 in response to a tensile force on whipstock 10.

In FIG. 4 the arrangement of the gripping is the same as FIG. 2 in thatthere is a slip 36 located 180 degrees opposite a segment 62 withhardened or carbide inserts 64. As before pressure in line 14 goesthrough check valve 16 and against piston 80 that has a peripheral seal82. Spring 84 pushes piston 80 away from slip 36 until the spring forceis overcome with pressure in line 14. Piston 80 has a through bore 78blocked by plug 86 that has a seal 88. A battery and signal receiver 90gets a remote signal to close a circuit which then heats a wire 92operatively connected to retainer 94 to defeat it which constitutes thetrigger so that plug 86 can move and take seal 88 past vent passage 96to relieve the pressure above piston 80 which in essence allows spring84 to push piston 80 away from slip 36 to allow removal of the whipstock10 without well intervention which means avoiding sticking tools in theborehole to accomplish the task. Again in this version the hardenedinserts 38 in slip 36 are parallel to hardened inserts 64 in segment 62,but are at a small angle with respect to whipstock axis 152 of thewhipstock 10 such that extension of slip 36 until inserts 64 reach thesurrounding tubular 180 degrees away will wind up pushing the top end ofthe whipstock against the surrounding pipe to keep it out of the way ofthe advancing window mill. Surface 98 is stationary as the slip 36 isguided at end 100 by a rail or dovetail. In this design the line 14pressure held by check valve 16 holds the set position of the slip 36.

The signal can be sent without well intervention in a variety of knownways such as acoustic, electromagnetic, mud pulse or vibration. A fixedlug retrieval tool that engages the whipstock for whipstock retrievalcould mechanically close a circuit that would initiate opening of thetrigger. The fixed lug retrieval tool could include a magnet thatactivates a sensor in the whipstock. Using the fixed lug retrieval toolto initiate pressure release could include running a wire from thewhipstock to the battery. That is, a sensor is optional in the anchor.Closing the circuit to active the pressure release could be controlledfrom the whipstock instead of at the anchor.

FIG. 5 uses line 14 and check valve 16 to feed pressure to radiallyextend pistons 110 that each have hardened or carbide inserts 112.Located 180 degrees opposite are fixed inserts 114, that are parallel tohardened inserts 112, but at an angle with respect to whipstock axis152. There are return springs 116 on each piston 110. The release systemin FIG. 5 works the same way as in FIG. 4 in response to a remote signalto vent pressure and allow return springs 116 to retract the pistons110. As with FIG. 4 the applied line 14 pressure trapped by the checkvalve 16 holds the set position. Any different amount of pistons 110 canbe used and some can be articulated in a 180 degree opposed orientation.As before a retainer 42 limits the extension of the pistons when thereis no surrounding tubular present.

FIG. 6 is intended to show that cap 22 of FIG. 1 can be removed atthread 24. When that happens cone 32 can be converted to set down weightoperation against hole bottom. Alternatively, a packer module 120 can beattached at thread 24 to in essence recreate chamber 20 for operation ofcone 32 as in FIG. 1 but to also extend a passage for hydraulic pressureto port 122 to drive piston 124 against seal assembly 126 and againstfixed surface 128 so that slips 36 can be extended as well as a sealassembly 126. A lock ring 130 holds the set of the seal assembly 126. Asbefore a tensile force on the whipstock 10 creates a tensile failure atnecked down portion 60 to allow release of at least the slips 36.

FIG. 7 has a slightly different release system that acts to underminethe lock ring 44. The layout is similar to FIG. 4 with the differencebeing that actuation of plug 86 by system 90 based on a remote signalmoves seal 88 past passage 96 to allow fluid in chamber 130 to reachlock ring 44 and undermine it with chemical attack or an equivalent way.

Those skilled in the art will appreciate that the various designalternatives presented show a whipstock anchor that can be hydraulicallyset and can hold the set position with a check valve on the hydraulicline. Alternatively a lock ring can hold the set position and releaseoccurs when a tensile force results in tensile failure of a mandrel torelease the hydraulic pressure. Alternatively a release of hydraulicpressure can be remotely actuated with release of a retained plug whosemovement vents hydraulic pressure or disables or undermines a lock ringchemically. A single piston can extend a slip with movement against afixed surface or two pistons can be pushed in opposed directions.Movable slips can be oriented in opposition to each other or a movableslip can be opposite a fixed slip with inserts. Cocking of the whipstockcan be accomplished by skewing the housing for the slips with respect toa whipstock axis or skewing the slip axis relative to an alignedwhipstock and anchor housing axis. The designs feature simplicity in ahydraulically set anchor for a packer with a resultant economy inmanufacturing. A removable cap can be used for hydraulic operation of apiston and with the cap removed for operating the piston with set downweight. A seal module can be secured in place of the end cap to allowsetting a packer with the anchor and to release the anchor and the sealassembly when necked down portion 60 is broken.

The above description is illustrative of the preferred embodiment andmany modifications may be made by those skilled in the art withoutdeparting from the invention whose scope is to be determined from theliteral and equivalent scope of the claims below:

We claim:
 1. An anchored borehole tool assembly, comprising: a boreholetool; an anchor housing featuring at least one radially extendible slipactuated by at least one piston selectively operated by hydraulicpressure provided into said housing; said housing further comprising apressure retaining device to hold said at least one slip extended byholding hydraulic pressure applied to said housing.
 2. The assembly ofclaim 1, wherein: said hydraulic pressure in said housing is relievedwith failure of a component in said housing allowing said slip to beretracted.
 3. The assembly of claim 1, wherein: said hydraulic pressurein said housing is relieved with opening a vent valve in said housingallowing said slip to be retracted.
 4. The assembly of claim 1, wherein:said hydraulic pressure in said housing is relieved with undermining atleast one locking member for said at least one slip in said housingallowing said slip to be retracted.
 5. The assembly of claim 4, wherein:said at least one locking member is undermined by opening a valve torelease a fluid to reach said at least one locking member.
 6. Theassembly of claim 5, wherein: said valve is signaled to open from aremote location without borehole intervention.
 7. The assembly of claim6, wherein: said valve comprises a selectively retained piston,whereupon said remote signal a restraint on said piston is removed suchthat piston movement opens a fluid reservoir to said at least onelocking member to undermine said at least one locking member with saidfluid.
 8. The assembly of claim 1, wherein: said piston moves axiallyfor radial extension of said slip.
 9. The assembly of claim 8, wherein:said hydraulic pressure in said housing is relieved with opening a ventvalve in said housing allowing said slip to be retracted.
 10. Theassembly of claim 9, wherein: said valve is signaled to open from aremote location without borehole intervention.
 11. The assembly of claim10, wherein: said valve comprises a selectively retained piston,whereupon said remote signal a restraint on said piston is removedallowing said piston to open a vent passage so that said at least oneslip can retract into said housing.
 12. The assembly of claim 3,wherein: said valve is signaled to open from a remote location withoutborehole intervention.
 13. The assembly of claim 12, wherein: said valvecomprises a selectively retained piston, whereupon said remote signal arestraint on said piston is removed allowing said piston to open a ventpassage so that said at least one slip can retract into said housing.14. The assembly of claim 13, wherein: said at least one piston isspring biased to a position where said at least one slip is retracted.15. The assembly of claim 7, wherein: said at least one piston is springbiased to a position where said at least one slip is retracted.
 16. Theassembly of claim 11, wherein: said at least one piston is spring biasedto a position where said at least one slip is retracted.
 17. Theassembly of claim 1, wherein: said at least one piston is selectivelymechanically operated for extension of said at least one slip byexposing said at least one piston with removal of a cover on saidhousing.
 18. The assembly of claim 1, wherein: removal of a cover onsaid housing adapts said housing to accept a packer assembly forhydraulic operation using the hydraulic pressure in said housing thatoperates said at least one slip.
 19. The assembly of claim 1, wherein: amandrel is surrounded by said at least one piston; movement of saidpiston relative to said mandrel is locked with a locking member againstreverse movement of said at least one piston; said mandrel having adecreased dimension portion that breaks or fails in response to atensile force on said tool transmitted to one end of said mandrel withan opposing end of said mandrel retained by said at least one slipresisting said tensile force through said at least one piston and saidlocking member; said breaking or failing of said decreased dimensionportion of said mandrel allows a portion of said mandrel to move awayfrom said at least one slip for retraction of said at least one slip.20. The assembly of claim 1, wherein: said at least one slip comprises aplurality of pistons disposed for movement in opposite directions towardsaid at least one slip with each piston locked against reverse movementaway from said at least one slip.
 21. The assembly of claim 1, wherein:said tool has a first longitudinal axis and said slips have a secondlongitudinal axis that is skewed with respect to said first longitudinalaxis such that extension of said at least one slip cocks an end of saidtool toward a wall of the borehole.
 22. The assembly of claim 1,wherein: said at least one slip comprises a plurality ofcircumferentially spaced slips each of said slips having opposed endtapers that slide on opposing ramps, wherein said tapers have the sameangle with said opposing ramps at different angles or said tapers havethe different angles with said opposing tapers having the same anglesuch that extension of said slips cocks an end of said tool toward awall of the borehole.
 23. The assembly of claim 9, wherein: said toolcomprises a whipstock; said valve is opened with intervention of aretrieval tool for said whipstock.
 24. The assembly of claim 9, wherein:said signal comprises acoustic, electromagnetic, mud pulse or vibration.25. An anchored borehole tool assembly, comprising: a borehole tool; ananchor housing featuring a plurality of radially extendible slipsactuated by at least one piston selectively operated by hydraulicpressure provided into said housing; wherein radial extension of saidslips skews the axis of at least said borehole tool with respect to anaxis of the borehole.
 26. The assembly of claim 22, wherein: said slipshaving different widths on opposed sides of a retainer to insure theproper installation orientation.
 27. The assembly of claim 1, wherein:said at least one slip comprises a plurality of circumferentially spacedslips; said slips are axially offset to skew said anchor housing uponradial extension of said slips.
 28. The assembly of claim 25, wherein:said piston moves axially for radial extension of said slips.
 29. Theassembly of claim 25, wherein: a mandrel is surrounded by said at leastone piston; movement of said piston relative to said mandrel is lockedwith a locking member against reverse movement of said at least onepiston; said mandrel having a decreased dimension portion that breaks orfails in response to a tensile force on said tool transmitted to one endof said mandrel with an opposing end of said mandrel retained by saidslips resisting said tensile force through said at least one piston andsaid locking member; said breaking or failing of said decreaseddimension portion of said mandrel allows a portion of said mandrel tomove away from said slips for retraction of said slips.
 30. The assemblyof claim 25, wherein: said tool has a first longitudinal axis and saidslips have a second longitudinal axis that is skewed with respect tosaid first longitudinal axis such that extension of said slips cocks anend of said tool toward a wall of the borehole.
 31. The assembly ofclaim 25, wherein: said slips are circumferentially spaced such thateach of said slips comprises opposed end tapers that slide on opposingramps, wherein said tapers have the same angle with said opposing rampsat different angles or said tapers have the different angles with saidopposing tapers having the same angle such that extension of said slipscocks an end of said tool toward a wall of the borehole.
 32. Theassembly of claim 31, wherein: said slips having different widths onopposed sides of a retainer to insure the proper installationorientation.
 33. The assembly of claim 28, wherein: two said radiallyextendable slips are axially offset to skew said anchor housing uponradial extension of said slips.
 34. The assembly of claim 27, wherein:said piston includes ramp surfaces that are axially offset to engagedtapered surfaces on two said radially extendible slips to skew saidanchor housing upon radial extension of said slips.
 35. The assembly ofclaim 33, wherein: said anchor housing includes ramp surfaces that areaxially offset to engaged tapered surfaces on two radially extendibleslips to skew said anchor housing upon radial extension of said slips.